| Response of yield components, and fruit composition of 'Chambourcin' grapevines to three pruning levels of 15, 20 and 25 nodes retained for each 454 g of dormant prunings; and three cluster thinning levels of 1, 2 and 2+ clusters per shoot in 2002 and 1, 1.2 and 1.5 clusters per shoot in 2003 was measured. Vine size was lower across all treatments in 2002 compared to 2003. In 2003, as pruning severity increased, the proportion of count shoots to non-count shoots decreased (62% of total) and yield decreased, but total soluble solids (TSS) and pH of juice increased. In both years, as cluster thinning severity increased, yield decreased and TSS increased. Balanced pruning to 15 to 20 nodes per 454 g of prunings and cluster thinning of 1 to 1.2 clusters -shoot-1 optimized yield 9.7 kg·vine-1, 13.4 tonnes·ha -1, and fruit composition; and maintained vine size (≥0.3 kg·m -1 of row).; Increasing cluster thinning increased periderm browning and primary bud cold hardiness. Pruning and cluster thinning did not affect whole vine photosynthesis (A), but at harvest A was 1.8 times greater than at berry touch, veraison or post-harvest. Optimum leaf area:fruit ratio (between 10 and 14) was obtained with pruning to 15 or 20 nodes for each 454 g of prunings and retaining 1 or 1.2 clusters per shoot, which corresponded to decreased cane die-back, increased periderm browning, and primary bud cold hardiness.; Geographic information system (GIS) technologies were utilized for suitability analysis of vineyard sites in southern Illinois. A model included growing degree-day summation and occurrence of -26°C between 1969--2002, absolute elevation, slope and soils that drained well or moderately well with moderate organic matter content. The resulting layers were overlaid and suitability maps were developed. In the study area, over 18,155 hectares of land highly suitable or suitable for viticulture was identified. Existing orchard and vineyard acreage (223 ha) in the study area were surveyed. Of the surveyed vineyard acreage, over 81% of them lies within the suitable or better ranking according to the model. Of the surveyed orchard acreage, over 50% of them lies within the suitable or better ranking. |
